Liquid crystal display

A liquid crystal display (LCD) is an electronically-modulated optical device shaped into a thin, flat panel made up of any number of color or monochrome pixels filled with liquid crystals and arrayed in front of a light source (backlight) or reflector. It is often used in battery-powered electronic devices because it requires very small amounts of electric power.

A comprehensive classification of the various types and electro-optical modes of LCDs is provided in the article LCD classification.

Inverter

An inverter is an electrical device that converts direct current (DC) to alternating current (AC); the resulting AC can be at any required voltage and frequency with the use of appropriate transformers, switching, and control circuits.

Static inverters have no moving parts and are used in a wide range of applications, from small switching power supplies in computers, to large electric utility high-voltage direct current applications that transport bulk power. Inverters are commonly used to supply AC power from DC sources such as solar panels or batteries.

The electrical inverter is a high-power electronic oscillator. It is so named because early mechanical AC to DC converters were made to work in reverse, and thus were "inverted", to convert DC to AC.

The inverter performs the opposite function of a rectifier.

Australia

Whereas the original bobbers and choppers were mostly home built on a budget, the modern development of the chopper tends to be shop built and very expensive. It differs from what has gone before in the technology employed in frame construction and the use of billet aluminium parts... headlights, foot and hand controls etc. Almost all 'Longbikes' have 'Big Inch' after market or current Harley Davidson motors. Paint work styles tend to favour ghostly air brushing techniques and the Longbikes are almost exclusively solo.

However the home built Bobber, Old School and Classic choppers are enjoying a comeback around the world and in Australia.

In Australia, many choppers built in the seventies are being brought out of 'retirement' and appearing again on our streets. Older bikes from this period; Honda CB750/4's, Yamaha XS 650's and Triumphs 750's and 650's are being purchased and chopped like they were 'back then'. Because of their reliability, modern Japanese and British 'cruisers' are also getting chopped, though this is more difficult because of Australia's restrictive regulations on modern machines. This current crop of home builders is a fairly even mix of guys in their 40's and 50's who built a chopper in the 70's and 80's and young blokes who've been inspired to emulate a unique period of Australian motorcycle history.

In most Australian states, Australian Design Rules limit frame modifications (engineer's certificate required), and fork extension (6"). The most restrictive rule is one that allows a maximum distance of 550mm from the front axle horizontally back to the steering head. Noise restrictions and handlebar dimensions are also regulated. In some states ADR's do not apply to pre 1977 motorcycles, so some of the older more radical choppers are still seen on Australian roads.

Today's chopper era

Choppers have enjoyed a large following. Companies like Jesse G. James' West Coast Choppers have been successful in producing expensive traditional chopper-style bikes and a wide range of chopper-themed brands of merchandise such as clothing, automobile accessories and stickers.

A distinction should be noted between true chopper (or chopper-style) motorcycles, and custom motorcycles, or 'custom cruisers'. Despite the name, a large percentage of the motorcycles produced by popular companies such as Orange County Choppers, Indian Larry, Falcon Motorcycles, Warlock Motorcycles, and Von Dutch Kustom Cycles are better described as 'custom' bikes rather than choppers.

A distinction should also be made between choppers and bobbers. While both tried to improve performance by removing any part that did not make the motorcycle perform better, they differed in an important way: bobbers kept the original factory frame, while choppers have a modified form of the factory frame.

When individuals were stripping their stock motorcycles and bobbing their fenders, the term "bobber" was born. When individuals started cutting (or chopping) and welding their frames thereby repositioning/restyling them, the term "chopper" was born. Chopping was the next phase in the evolution that followed dirt track bobbing.

While people assume that the chopper style motorcycles were built purely for aesthetics, there is a real performance advantage to the raked front end on these choppers. These motorcycles have a much more stable feel at high speeds and in a straight line than motorcycles with original factory front suspensions. However, like any other modification, there is a downside: the raked front end feels heavier and less responsive at slow speeds or in curves and turns. This is due to the longer trail measurement associated with increased rake.

Changing the rake and trail of a motorcycle design requires modification of the design itself. This is a job that requires in-depth input from a motorcycle designer who is experienced with such design changes.

Which brings up one more option a chopper builder has: raked trees. Raked trees are designed so the lower tree sticks out further than the upper tree, thus increasing the rake of the forks in relation to the steering head rake. What this does, for those still following along all the imaginary lines, is position the axle closer to the frame rake measurement line, or shortening the trail. Thus, when adding raked trees to a raked frame (which sports a longer trail), the trail is shortened to a more manageable level. However, be warned that adding raked trees to a frame with short rake and trail can be hazardous, as shortening an already short trail measurement can lead to an unstable situation as speed increases. Misuse of raked trees can be quite dangerous, so a bit of research is in order before turning the first wrench on any chopper project. Just remember that because it looks good in a magazine doesn't automatically mean it will work on your bike.

Despite the personalized nature of choppers, and the wide availability of alternative designs, chopper builders have overwhelmingly chosen fat rear tires, a rigid-looking frame (even for a softail), and an original or replica air-cooled, pushrod v-twin engine. In the UK, due to the cost and lack of availability of the v-twin engine, many chose to use British engines from bikes such as Triumph or BSA; lately as availability has increased, Japanese engines have seen more use. Some people feel that the variety of engines and other components used more recently (especially on bikes built outside of the US) is diluting the signature appearance of the chopper style. Modern bobber builders tend to distinguish themselves from chopper builders with bikes styled before the chopper era. Modern bobber builder Jan Bachleda (originally from Slovakia) of JBIKEZ [1]

in Colorado builds custom choppers and bobbers using Triumph engines and frames from the 1970s and earlier. The look, though chopped, is distinctly modern and low. Today's custom choppers are usually seen as center pieces at bike night events around the United States. [


The United States of America, where most custom choppers reside, is one of the few countries in the world that allow custom-built choppers to be licensed for highway use. Many of these types of choppers are regarded as dangerous to operate and don't follow basic design geometry and lack many safety features in their construction.

Finally, an often overlooked style of chopper is the chopper bicycle. Inspired by the smooth, low lines of chopper motorcycles, today's custom chopper bicycle designer builds bicycles that pay tribute to the motorcycles they resemble.

Chopper (motorcycle)

In the post-World War II United States, servicemen returning home from the war started removing all parts deemed too big, heavy, ugly or not absolutely essential to the basic function of the motorcycle, such as fenders, turn indicators, and even front brakes. The large, spring-suspended saddles were also removed in order to sit as low as possible on the motorcycle's frame. These machines were lightened to improve performance for dirt-track racing and mud racing.

Forward-mounted foot pegs replaced the standard large 'floorboard' foot rests. Also, the standard larger front tire, headlight and fuel tank were replaced with much smaller ones. Many choppers were painted preferably all in either flat black or in shiny metallic “metal flake” colors. Also common were many chromed parts (either one-off fabricated replacements or manually chromed stock parts). According to the taste and purse of the owner, “chop shops” would build high handle bars, or later “Big Daddy” Roth Wild Child’s designed stretched, narrowed, and raked front forks. Shops also custom built exhaust pipes and many of the “after market kits“ followed in the late 1960s into the 1970s. Laws required (and in many locales still do) a retention fixture for the passenger, so vertical backrests called sissy bars were a popular installation, often sticking up higher than the rider's head.

While the decreased weight and lower seat position improved handling and performance, the main reason to build such a chopper was to show off and provoke others by riding a machine that was stripped and almost nude compared to the softer-styled stock Harley-Davidsons, let alone the oversized automobiles of that time.

Traditional choppers

In the United States servicemen returning from World War II were looking for a thrill. Many veterans had been trained to work on automobiles and motorcycles and were looking to add a little excitement to their post-war lives with their newly acquired mechanical skills. Motorcycles and Hot Rods were the perfect hobby for them. Motorcyclists bought up surplus military bikes and removed all the unnecessary parts like windshields and saddlebags to minimise weight. Rear fenders were "bobbed" or shortened just enough to handle a passenger and keep the rain and mud coming off the rear, and sometimes removed the mirrors, or replaced them with tiny ones, such as the type used by dentists in their work.

This type of home customization led to the rise of the "bobber". Then in the 60s, motorcyclists found that a longer front end allowed the bike to run smoother at faster speeds. The degree of neck rake and length of front end was modified on these bikes with this in mind. The Girder and Springer front ends were the most popular forks for extending in this fashion, although this does make the bike harder to handle at slower speeds. Nevertheless, some choppers have extremely long forks; as one biker said, "You couldn't turn very good but you sure looked good doing it." [

To build or chop a traditional chopper an unmodified factory bike is used (usually a rigid Harley Davidson) and everything unnecessary to either move or stop is stripped or chopped off. Then the engine and transmission are removed and the frame is cut up and welded back together to make it lower and lighter. Performance parts are added or modified to increase speed.

Role in modern personal computers

In the book PC 97 Hardware Design Guide,[3] Microsoft deprecated support for the RS-232 compatible serial port of the original IBM PC design. Today, RS-232 is gradually being replaced in personal computers by USB for local communications. Compared with RS-232, USB is faster, uses lower voltages, and has connectors that are simpler to connect and use. Both standards have software support in popular operating systems. USB is designed to make it easy for device drivers to communicate with hardware. However, there is no direct analog to the terminal programs used to let users communicate directly with serial ports. USB is more complex than the RS-232 standard because it includes a protocol for transferring data to devices. This requires more software to support the protocol used. RS-232 only standardizes the voltage of signals and the functions of the physical interface pins. Serial ports of personal computers are also often used to directly control various hardware devices, such as relays or lamps, since the control lines of the interface could be easily manipulated by software. This isn't feasible with USB, which requires some form of receiver to decode the serial data.

As an alternative, USB docking ports are available which can provide connectors for a keyboard, mouse, one or more serial ports, and one or more parallel ports. Corresponding device drivers are required for each USB-connected device to allow programs to access these USB-connected devices as if they were the original directly-connected peripherals. Devices that convert USB to RS-232 may not work with all software on all personal computers and may cause a reduction in bandwidth along with higher latency.

Personal computers may use the control pins of a serial port to interface to devices such as uninterruptible power supplies. In this case, serial data is not sent, but the control lines are used to signal conditions such as loss of power or low battery alarms.

Certain industries, in particular marine survey, provide a continued demand for RS-232 I/O due to sustained use of aging, high-cap-ex equipment. Some manufacturers have responded to this demand: Toshiba re-introduced the DB9 Male on the Tecra laptop. Companies such as Digi specialise in RS232 I/O cards.

Limitations of the standard

Because the application of RS-232 has extended far beyond the original purpose of interconnecting a terminal with a modem, successor standards have been developed to address the limitations. Issues with the RS-232 standard include:

* The large voltage swings and requirement for positive and negative supplies increases power consumption of the interface and complicates power supply design. The voltage swing requirement also limits the upper speed of a compatible interface.
* Single-ended signaling referred to a common signal ground limits the noise immunity and transmission distance.
* Multi-drop connection among more than two devices is not defined. While multi-drop "work-arounds" have been devised, they have limitations in speed and compatibility.
* Asymmetrical definitions of the two ends of the link make the assignment of the role of a newly developed device problematic; the designer must decide on either a DTE-like or DCE-like interface and which connector pin assignments to use.
* The handshaking and control lines of the interface are intended for the setup and takedown of a dial-up communication circuit; in particular, the use of handshake lines for flow control is not reliably implemented in many devices.
* No method is specified for sending power to a device. While a small amount of current can be extracted from the DTR and RTS lines, this is only suitable for low power devices such as mice.
* While the standard recommends a 25-way connector and its pinout, the connector is large by current standards.

RS-232

In telecommunications, RS-232 (Recommended Standard 232) is a standard for serial binary data signals connecting between a DTE (Data Terminal Equipment) and a DCE (Data Circuit-terminating Equipment). It is commonly used in computer serial ports. A similar ITU-T standard is V.24.

History
The original DTEs were electromechanical teletypewriters and the original DCEs were (usually) modems. When electronic terminals (smart and dumb) began to be used, they were often designed to be interchangeable with teletypes, and so supported RS-232. The C revision of the standard was issued in 1969 in part to accommodate the electrical characteristics of these devices.

Since application to devices such as computers, printers, test instruments, and so on was not considered by the standard, designers implementing an RS-232 compatible interface on their equipment often interpreted the requirements idiosyncratically. Common problems were non-standard pin assignment of circuits on connectors, and incorrect or missing control signals. The lack of adherence to the standards produced a thriving industry of breakout boxes, patch boxes, test equipment, books, and other aids for the connection of disparate equipment. A common deviation from the standard was to drive the signals at a reduced voltage: the standard requires the transmitter to use +12V and -12V, but requires the receiver to distinguish voltages as low as +3V and -3V. Some manufacturers therefore built transmitters that supplied +5V and -5V and labeled them as "RS-232 compatible."

Later personal computers (and other devices) started to make use of the standard so that they could connect to existing equipment. For many years, an RS-232-compatible port was a standard feature for serial communications, such as modem connections, on many computers. It remained in widespread use into the late 1990s. While it has largely been supplanted by other interface standards, such as USB, in computer products, it is still used to connect older designs of peripherals, industrial equipment (such as based on PLCs), and console ports, and special purpose equipment such as a cash drawer for a cash register.

The standard has been renamed several times during its history as the sponsoring organization changed its name, and has been variously known as EIA RS-232, EIA 232, and most recently as TIA 232. The standard continued to be revised and updated by the Electronic Industries Alliance and since 1988 by the Telecommunications Industry Association (TIA).[ C was issued in a document dated August 1969. Revision D was issued in 1986. The current revision is TIA-232-F Interface Between Data Terminal Equipment and Data Circuit-Terminating Equipment Employing Serial Binary Data Interchange, issued in 1997. Changes since Revision C have been in timing and details intended to improve harmonization with the CCITT standard V.24, but equipment built to the current standard will interoperate with older versions.

DAQ Introduction - Digital Inputs

Data Acquisition devices provide an interface between electrical signals a computer can read or write to control things in the real world.

A computer is equipped with various communication ports to access the outside world, but it needs software to read and write to them, as well as display data or accept user input.

In the early days of PC’s a user could use a simple programming language to write a program that would access the ports using direct port-in and port-out commands and read or set the value. Examples of digital inputs or outputs could be found in computers with joystick and trigger inputs, and in the parallel port control line outputs such as strobe, and control line inputs for busy, paper error, ack, and the 8 bits of data output. With a joystick port, there were digital inputs for trigger and analog inputs for joystick position.

With a digital input we can read two states, a high or low. A switch can be open or closed.
With a digital output, we can turn a light on or off, control a relay or turn a motor on or off. If we can turn a digital output on/off rapidly enough, we can vary the on/off time for PWM (Pulse Width Modulation) and effectively develop a average DC voltage anywhere between full on, full off, or with a 50% duty cycle, half the source voltage.

USB: Adaptable for Industrial Applications

The Universal Serial Bus (USB) provides a high data rate and Hot Swap connection for PCs, providing an easy connection to a wide variety of multimedia and network USB devices. Generally considered to be for home or office use, USB is finding its way into Industrial applications.

What might USB offer the industrial environment? With USB, there is a medium bandwidth non-proprietary port made available on PC's. USB data uses a multidrop, half-duplex twisted pair, similar in operation to a two-wire RS-485 system. This differential signaling offers a reasonable amount of noise immunity for harsh environments. Power is distributed on the bus as well. Low power peripherals have no problem operating without an external power supply.

Data rates are high; the USB bus operates at a maximum of 12 Mbps. This opens many possibilities for low cost data acquisition equipment without the burden of proprietary ISA or PCI bus cards competing for space inside the PC. The multidrop and Hot Swap nature of the bus allows many USB devices to be mixed and matched on the same bus. This provides improved configuration flexibility over traditional serial and parallel ports.

Many Industrial devices and networks use a direct interface to a PC for programming, monitoring, data collection, and diagnostics of the Industrial buss. The use of laptop computers has been a convenient tool for accessing these networks. With most laptops coming with USB ports and no serial ports, devices that help connect a USB port to an Industrial buss have been increasingly popular.

However, USB was not designed with industrial applications in mind. Distances are very limited; any bus segment cannot exceed 5 meters, and there is no provision for signal isolation. These types of limitations are nothing new to those using PCs in industrial environments but need to be addressed for many applications.

USB requires extensive operating system support. The original release of Windows 95 did not include USB support, but Microsoft added USB support to Windows 95, labeling it OSR2.1 (also called Win 95b). USB support was included in Windows 98, 2000 and ME Operating Systems. Most PCs shipping after 1997 are equipped with USB ports and full USB Support.

Economics of scale have pushed the PC into widespread use in many industrial applications. USB is being carried into these environments as well and provides one more method of connecting the PC to the outside world.

USB

A new computer finally arrives. It has lightning speed, the latest operating system, and a RWCD. Then you notice the manufacturer has shipped the computer without the standard DB-9 serial ports. If a serial port is being used on the computer this is replacing, what can be done? There is an easy solution to this, the USB to Serial converter.

Most computers today will ship with at least two USB ports. For a lot of individuals, this will not be enough to handle all the devices that need to connect to the computer. For example a USB mouse and keyboard are common, and when a printer and Personal Data Assistant is added it can be seen that more ports are needed.

The easiest solution to this is to add a USB hub. Most hubs will support the addition of four or more peripheral devices. Hubs can be added to extend the distance a USB device can be away from the computer, along with adding ports. The maximum distance a standard USB cable should be is 5 meters. With the addition of USB hubs the distance can be extended to 30 meters using a 5-meter cable between each hub.

Windows operating systems that support USB (Windows 98 SE, ME, 2000 and XP) will automatically detect the USB peripheral device when connected to the USB port. The setup wizard steps through the installation asking for the drivers and setting up the Com Port when installing USB to serial converters. After a USB device is configured in an operating system the device can be connected and disconnected at any time.

USB also provides a solution for parallel printers that are currently connected to parallel ports and do not have USB support. These are designed to work exclusively with printers. Standard USB to parallel converters are also available.

A lot of development is underway to allow an easy transition to USB by many companies. One example would be USB devices that are now available allowing Windows NT 4.0 operating systems, which normally will not support USB, access to USB ports. The purpose of this is to facilitate the addition of several serial ports or a printer port to the computer with a single USB connection. A single USB device may contain four serial ports or two serial ports and a parallel printer port. For most users this may be easier than the traditional methods of adding ports to a computer.

Most USB to serial converters will load in the operating system and show up in the device manager as a new Com Port. Most install on the next available Com Port in the operating system. At this time the USB to serial converters include a RS-232 or RS-422/485 interface. Converters can also include optical isolation for use in harsh environments.

To incorporate USB with currently used software is a workable solution for most users. Only programs designed to communicate to an I/O address and IRQ are the exception. Most programs that have been written and use the normal Windows API call will be able to access a USB port. RS-232 converters can include full hand shaking capabilities if supported by the software being run on the computer. Hyper Terminal is an example of a program found commonly on Windows operating systems which will support any USB or serial COM Port that loads on COM 1-4. Other software programs will commonly support most USB COM Port numbers that load above COM 4.

The introduction of USB may seem a little confusing but with the correct support from manufacturers the users will find it a useful and easy transition.

EXTENDED VLAN

Network Topology, Configuration and Hardware: Industrial VLAN Best Practices

Industrial VLANs use a wide variety of configurations and equipment. Part of the attraction of Ethernet VLANs is that legacy devices, wiring and topology can be used as part of a full system of VLANs.

Managed switches make it possible to create and manage VLANs, and the right industrial switch can save a lot of trouble. An industrial managed switch should have the right number and kind of ports, strength, dependability and ultra fast recovery for the real needs of the industrial settings*. The need for reliable ruggedness typically exceeds that of commercial installations. Data flow rates can be controlled to avoid problems. The fastest ports available on each switch should be used for network trunk links, as these carry the most traffic.

Switch and router placement makes a difference. Inefficiencies may arise if they aren’t located the shortest physical distance to the maximum number of nodes on the VLAN. Longer paths increase the likelihood of failures and
complicate problem diagnosis.

Unshielded twisted pair (UTP) cable is the most commonly used wiring. At many plants is this is already in place, often making a VLAN possible without running new cable. Fiber optic cable carries more data over greater distances, and is useful for network trunk links.

Management Software for industrial VLANs should be graphic oriented. In non-industrial settings it’s presumed that everyone dealing with the network went to IT school. But industrial automation is very visual, and plant personnel are often the first responders to VLAN issues. They’re much more used to dealing with colors and check boxes than a command line interface.

Packet Filtering – Tag VLAN headers may cause trouble on industrial networks. It’s OK to leave the tag data on packets going to tag-aware devices. But if all devices aren’t tag-aware, the switch must strip tags from packets before they go out to the VLAN. This is very important in dealing with the legacy equipment found in many industrial settings.

Redundancy is a key to reliable operation. Though industrial equipment typically withstands far more abuse than commercial, the nature of many industrial networks makes back-up systems necessary. A degree of redundancy is often the best way to ensure network stability. And in some situations full redundancy is both needed and available.

*Equipment capability - The best equipment is “tuned” to the needs of the specific industrial situation. An outstanding example of how to do this is B&B Electronics’ robust line of Elinx 500/600 Managed Industrial Switches.

Benefits of Industrial VLANs

Isolation – VLANs isolate network traffic to accommodate differences in operational needs.

Simplicity – As networks grow, they can turn into difficult to manage monsters. By segmenting networks, VLANs make them easy to understand, change, and troubleshoot.

Speed and Performance – VLANs reduce delays, also called latency, by reducing the size of the collision domain. Broadcast traffic is reduced, since it doesn’t go past its own VLAN.

Scalability – A VLAN may be as small as a single port on one switch, or span any size organization.

Flexibility – Additions and changes are simple. Moving a user to a different VLAN is just a matter of reconfiguring the port. And different operating systems can coexist on a single network, as long as each is on its own VLAN.

Cost – Subdividing networks using VLANs saves money over buying separate physical networks.

Security – Securing data is a great reason for using VLANs. Also, as priorities change, they can be adapted to the situation. For example, an IT department’s security protocols may differ from the manufacturing department, where reliability is often more important than security. While they don’t guarantee security, data from one VLAN can’t accidentally leak to another, regardless of shared cables, networks, routers or switches.

Special Applications – VLANs may be required wherever bandwidth or operational concerns create conflicts with other areas.

Port Or Tag VLAN?

Port based VLANs are suitable for smaller settings. As the name implies, ports are assigned to VLANs, and all users on a single port are members of the same VLAN. This allows the separation of office computers from industrial electronic devices.

IEEE 802.1Q Tag VLANs are so called because a “tag” or header is added to data packets to identify which VLAN they belong to. The 802.1Q standard specifies how VLANs manage data flow across multiple switches.

Figure 2. IEEE 802.1Q Tag VLAN Header

VLAN Trunking – When more than one switch is involved, one port on each switch (a trunk port) communicates VLAN information to the other switches involved. The links between switches (trunk links) not only communicate where each link of a VLAN is located, they also transmit the actual data between switches, which is then delivered to the appropriate port and
device.

Trunking, when used regarding VLANs, refers to the combined connections and software that make switches and VLANs interconnect smoothly. GARP VLAN Registration Protocol (GVRP) is the standards based system used by many manufacturers. VLAN Trunking Protocol (VTP) is a proprietary system used when only Cisco switches are involved. Both accomplish the same thing.

Applications

User types, departments or operations may all be reasons to segment the network into VLANs. For example, a factory automation network has greatly differing needs from the building automation, office, IT or human resource network. Even within the industrial side of things, there may be no need for the operator interface, vision, motion or other systems to be on the same VLAN.

Here are some other advantages of segregation:

* A VLAN can isolate office and other network traffic from the factory automation network, eliminating the chance that outside traffic can flood and interfere with time critical control communications.
* Inventory control with Radio Frequency Identification (RFI) creates huge data streams. A VLAN limits this data to where it is needed. Video surveillance and other systems may also use lots of bandwidth and require a separate VLAN.
* Security is often the top priority for the IT department, while reliability is for manufacturing. Since these concerns may conflict, it just makes sense to be on separate VLANs.
* Functional differences may warrant separate VLANs, such as network management and monitoring.
* Groups of users in three separate buildings can all be part of the same VLAN, and at the same time, be completely isolated from all unnecessary traffic. Taken further, VLANs can be securely scaled beyond a single location, over a Wide Area Network (WAN) link if necessary.

Preventing Network Problems on the Plant Floor with VLANs

The success of Ethernet technology came about because of its cost, effectiveness and simplicity compared with other network schemes. The lure of linking large numbers of systems was powerful.

All this connectivity came at a price. As networks grew, data collisions and delays increased. These delays slowed Ethernet’s progress with industrial control networks, where guaranteed response times are so important.

Then switch technology entered the scene. With unique pathways to each port, switches reduce collisions. Switch costs came down and they became widespread in non-industrial Ethernet networks. Then the development of industrial-hardened switches allowed these to be used more widely in industry.

Switches by themselves don’t limit traffic, but facilitate it. This traffic, if left uncontrolled, could lead to congested bandwidth and “clogged arteries.”

Virtual Local Area Networks or VLANs use managed switches to balance this expanded connectivity with useful boundaries on data traffic. VLANs make networks more reliable, and this reliability is what makes VLANs so useful in industrial settings.

Industrial VLANs

A VLAN is a single broadcast domain, not limited by physical location. VLANs create logical separation of control networks within a physical network, dividing physical interfaces into useful groups.

VLANs are created using parts of a switch, full switches or multiple switches linked together. An administrator assigns ports to each VLAN. Each VLAN then functions as an independent switch, broadcast domain and network. Each device on a VLAN has its own Media Access Control (MAC) address. MAC addresses are assigned by the manufacturer, and the VLAN uses these to tell where data goes.

Each VLAN is in effect a separate network. The only way to get data to a device on another VLAN is to send it outside the VLAN through a router – even if the receiving device is on a port on the same switch but on another VLAN.

Figure 1. Examples, Industrial VLAN Components

Power over Ethernet (PoE)

With the introduction of new Ethernet-enabled devices expanding geometrically, the need to power these devices from standard AC power outlets has become a limiting factor. IP telephones, wireless access points, IP cameras and device servers are examples of devices limited by the need to have an AC power outlet nearby to plug in a DC power adapter. At best, power supply installation and wiring adds labor and results in the mess of extra wiring; worst case, the lack of nearby AC power means devices cannot be installed where they are needed.

In response to this need, IEEE developed IEEE802.3af to standardize a system of supplying low voltage power to networked devices via the communications line. Released in mid-2003, the standard was entitled: Data Terminal Equipment (DTE) Power via Media Dependant Interface (MDI). It is more commonly referred to as Power over Ethernet (POE). PoE supplies power to network devices over the same standard Category 5e (CAT-5) cabling that carries the data. Devices can be installed wherever structured Ethernet wiring is located, without the need for AC power outlets nearby.

The benefits of PoE include increased mobility for end devices, added safety (no AC power involved), simplicity of installation, reliability, security and cost savings. These advantages have led to the development of a variety of new PoE-enabled products (including B&B Electronics’ PES1A and PESV1A RS-232 to Ethernet Converters).
How PoE Works

In the PoE scheme, two different types of devices are involved: Power Sourcing Equipment (PSE) and Powered Devices (PD).

PDs are PoE-enabled network end devices equipped to accept low voltage power transmitted over structured Ethernet CAT-5 cabling.

PSEs provide the DC power to PDs. PSEs source up to 12 watts at 48 volts to each PD. A PSE may be an endspan device or a midspan device. An endspan device typically is a network switch enabled to provide PoE power on each port. A midspan device is connected in-line to each end device and adds power to the line.

Power is carried over the cabling using two techniques: Alternative A and Alternative B

Alternative A implements a simplex, or ‘phantom feeding’ method for delivering power to the end device. Power is carried on the same conductors as data. CAT-5 cabling for standard 10BaseT and 100Base-TX Ethernet uses two data/signal pairs connected to pins 1 and 2 and pins 3 and 6 on RJ-45 connectors. Power sourcing equipment superimposes power onto these pins via the center tap of internal signal coupling transformers. In the powered device (PD) the power is derived from these lines using the reverse technique.

OVERVIEW OF ETHERNET

Here are the benefits gained by using Serial Servers:

1. Improved Access – Connect to serial devices over far greater distances.
2. Cost Effective - Communicate with serial devices without changing existing software.
3. Seamless Communications - Connectivity between serial devices over Ethernet is transparent to both the devices and the software.
4. Utilize Existing Equipment – Ethernet enable COM Ports.
5. Preserve Functional Legacy Networks - Connect serial networks as one or more subnetworks of the LAN.
6. Conserve Manpower - Remotely access serial devices.
7. Save Time - Update serial device software faster and easier using the Ethernet.

Serial to Ethernet: What To Look For

Not all means of bridging the Serial-to-Ethernet gap are equal. Here are a few things to look for and to consider:

* Hardware options – number of serial ports, desktop, panel and DIN-mount options.
* Support for RS-232, RS-422 and RS-485.
* “Tunneling” so the Ethernet is invisible to serial devices.
* Operating modes – virtual COM port, TCP/IP and UDP/IP.
* Multiple TCP client connections.
* Access to Serial Server menu settings, plus Telnet and Console modes to configure the server, allow remote upgrades, system defaults restoration, and select serial port settings.
* A web server for management from any web browser.
* Options for any PC on the network to correct problems.
* Software which allows easy access to the Serial Server for configuration, upgrades and analysis of firmware, port and hardware status.
* Ability to automatically reconnect the TCP link when it is lost.
* IP30 rated enclosure in industrial environments.
* Slim profile, DIN rail or panel mount options.
* Wide operating temperature range.
* Virtual COM support for the PC
* Modbus TCP/IP Capability

Application examples

There is no apparent limit to Serial Server applications, but some are more common. Usual configurations include camera and light controls, building security, traffic management systems, retail and point of sale devices.

Industrial devices such as PLCs, drives, motor controls and process analyzers are regular targets. Accessing serial devices through landline, cellular and satellite communications is also possible.

In short, serial servers present virtually unlimited options and possibilities and free up industrial environments to expand, modernize, and restructure with ease.

ETHERNET The Serial Revolution: Establishing Global Access to Serial Ports

In the process of updating a variety of computer systems and hardware configurations, the plant manager of a Midwest manufacturer needed a centralized network that would connect three buildings within three quarters of a mile, plus a couple more several miles away.

With a wide array of legacy equipment, primarily utilizing serial connections, the need presented a rather complex challenge, especially since serial connections are limited in terms of distance and networking.

The scenario is not uncommon. In fact, as computer software and hardware technologies advance, a massive connectivity gap is growing between perfectly good legacy systems and advanced Data Acquisition (DAQ), Programmable Logic Controllers (PLC), Industrial Computers and other critical systems.

Here are the challenges serial technology faces:

* Limits on linking remote equipment or networks,
* The number of potential connections is lower,
* Monitoring and control of remote equipment is more difficult,
* Upgrading software and firmware must be handled locally, and
* Various types of networks can’t talk to each other.

With recent advances, it’s now simple, fast and inexpensive to connect any number or type of serial equipment to an Ethernet network. The solution is utilizing Ethernet Serial Servers to make connections, manage traffic, and extending data signals to anywhere in the world.
History of Serial Communications

Serial ports were first used in 1960, and the first versions of RS-232 approved in 1969. The standards were intended for communications equipment such as phone modems, and serial interfaces were called COM ports.

Current maximum serial port speeds are 20 kilobits/second (Kbps) for RS-232 and 300 megabits/ second (Mbps) for RS-422/485. Distance limits are typically 50 ft. for RS-232 and 4,000 ft. for RS-422/485, though repeaters may extend this. The top number of devices for a serial LAN is 32; more can be connected with repeaters, up to the address limit (usually 256) of the devices used.

For years, advances in serial technology developed along with the equipment being connected. There are still many uses for serial devices, and the huge inventory of equipment, cables and software proves its success. Without question, serial connectivity remains the standard in a wide variety of industrial, commercial and medical applications

Even so, external serial ports are no longer standard on PCs. And serial technology is no longer a prime focus of development and progress. Herein lies the technology gap that is effectively bridged by Ethernet Serial Servers.
History of Ethernet LANs

In November of 1969 the U.S. Dept. of Defense sponsored a trial linking computers at UCLA and Stanford. It was the first effective joining of computers using different operating systems using the same communications protocols. This was accomplished over standard phone lines and with data speeds of 50 Kbps. It was the first true network operating system, and the predecessor of the Internet and Ethernet.

More computers were added, and eventually other networks developed and were linked. Research improved the technology. In 1974, basic principles of what was called the Ethernet were proposed and by1976 the first Ethernet was deployed, running at a speed of only 3 Mbps.

In the 1990’s, the Ethernet became the most frequently used of all local area networking (LAN) types, due to its speed, cost, versatility, dependability and ability to connect a variety of other network systems and equipment.

While the speed at which Ethernet can transfer data continues to increase, these blazing speeds have relatively little impact on moving serial originated data, where speeds are typically gauged in kilobits, not megabits.
Introduction to Ethernet Serial Servers.

Recently developed Serial-to-Ethernet technology makes it possible to connect serial devices using the Ethernet as a bridge. The cabling, hardware and software that accomplishes this is called Ethernet Serial Servers (or just Serial Servers for short).

Here is a simple layout of what might be accomplished when Ethernet is utilized in making connections:

Automatic Serial Data Collection

As more and more devices come equipped with some type of communication for data collection and monitoring, the amount of data that can be collected by a PC in a system is astounding. A problem arises, however, when multiple instruments or devices need access to the PC through the serial port, but only one port is available.

There are multiple options for expanding the capability of a port that was designed to communicate with only one device. You can add a separate serial port for each RS-232 device that you need to talk to. By adding serial ports, multiple devices can have their own dedicated port, often concurrently and at high speeds. The drawback is that separate serial ports may be expensive and require some effort to configure. There is also a practical limit on resources available inside the PC to allocate to Serial Ports.

Multiple devices can be tied together by converting the signal at each point to a multi-drop bus, like RS-485. This allows up to 32 devices on a single network without repeaters. The devices can also be connected up to 4000 feet away from the PC. The disadvantage is that each device must have its own unique address. Also, some protocol needs to be established to prevent more than one device at a time from sending data to the PC. Usually this is done by having the PC poll each device individually. This does not lend itself well to devices that send their data automatically, without being requested.

Using the 232BSS4 buffered Smart Switch is an excellent way to collect data from multiple devices utilizing RS-232 serial ports. Up to four instruments, card readers, or time clocks can be directly connected to the 232BSS4, providing access through a single serial port on your PC.

If you have more than four devices that are sending data, more than one 232BSS4 can be cascaded, allowing more ports to be added. The 232BSS4 buffers data from all ports at once, making it well suited for devices that will send a fixed amount of data at sporadic intervals, such as measurement instruments, security access card readers, barcode scanners, or time clocks. Below is an explanation of how best to utilize the 232BSS4 to connect these devices to your PC.>

RS 232

The serial port is prevalent on PC's as well as scores of industrial, scientific and consumer devices, making it a convenient starting point for communications. Since RS-232 itself is only suited to short connections (50 ft. max.) many applications require that it be adapted to fit requirements. RS-422, typically used for extending RS-232 communications, provides full duplex communications between two devices. It can also provide one way communications from one master to several slaves. RS-485 communications standard allows cable lengths up to 4000 feet. It also provides very high noise immunity. Multidrop connections up to 32 different nodes can be made over a single twisted pair cable along with a signal ground connection.

This article summarizes the choices a system designer has when adding a serial (RS-232, RS-422, or RS-485) communications device. There are many different ways to add additional serial ports to your Desktop PC, Palm, or Laptop PC. USB, PCMCIA, PCI and ISA are some of the methods that will be discussed.

The Universal Serial Bus (USB) provides a high data rate and Hot Swap connection for PCs, providing an easy connection to a wide variety of multimedia and network USB devices. Generally considered to be for home or office use, USB is finding its way into Industrial applications.

PCMCIA Serial Ports are yet another way to add serial ports to a PC that has PCMCIA Slots available. Most Laptops today offer only one (if any at all) DB9 type serial ports. A PCMCIA Serial Card is a good way to add a serial port (or ports) to any laptop that is low on available serial ports (RS-232, RS-422 or RS-485).

PCI Cards are becoming more popular as a way to add serial ports to desktop PC's. PCI type slots are becoming the "norm" in standard PC's today, and PCI Serial Cards are an excellent way to add serial ports. The standard Desktop PC may only come with one serial port standard (if any serial ports at all). PCI Serial Cards use Software Drivers to address the ports to the PC.

ISA Cards are yet another way to add serial ports to the older desktop PC's. ISA type slots are becoming scarce in standard PC's today, but are still an excellent way to add serial ports. The ISA Cards are typically addressed using dipswitches and shunts or jumpers to set IRQ's for each port. No Software Drivers are required with ISA style serial cards.

Palm OS PDA's may be connected to RS-422 or RS-485 data circuits using Palm adapters. These adapters offer total portability for collecting data and field service chores. The Palm device and the adapter will usually slip into a shirt pocket. Some models use the PDA's connecting cable, some include a cable and some are cradles that allow the PDA to nest in place and connect directly to the Palm base socket. PalmTerm Freeware allows you to transmit and receive data from the Palm serial port.

Cable Selection for RS-422 and RS-485 Systems

Selecting data cable for an RS-422 or RS-485 system isn't difficult, but often gets lost in the shuffle of larger system issues. Care should be taken, however, because intermittent problems caused by marginal cable can be very difficult to troubleshoot.

Beyond the obvious traits such as number of conductors and wire gauge, cable specifications include a handful of less intuitive terms.

Characteristic Impedance (Ohms): A value based on the inherent conductance, resistance, capacitance and inductance of a cable that represents the impedance of an infinitely long cable. When the cable is cut to any length and terminated with this Characteristic Impedance, measurements of the cable will be identical to values obtained from the infinite length cable. That is to say that the termination of the cable with this impedance gives the cable the appearance of being infinite length, allowing no reflections of the transmitted signal. If termination is required in a system, the termination impedance value should match the Characteristic Impedance of the cable.

Shunt Capacitance (pF/ft): The amount of equivalent capacitive load of the cable, typically listed in a per foot basis. One of the factors limiting total cable length is the capacitive load. Systems with long lengths benefit from using low capacitance cable.

Propagation velocity (% of c): The speed at which an electrical signal travels in the cable. The value given typically must be multiplied by the speed of light (c) to obtain units of meters per second. For example, a cable that lists a propagation velocity of 78% gives a velocity of 0.78 x 300 x 106 = 234 x 106 meters per second.
Plenum cable

Plenum rated cable is fire resistant and less toxic when burning than non-plenum rated cable. Check building and fire codes for requirements. Plenum cable is generally more expensive due to the sheathing material used.

The RS-422 specification recommends 24AWG twisted pair cable with a shunt capacitance of 16 pF per foot and 100 ohm characteristic impedance. While the RS-485 specification does not specify cabling, these recommendations should be used for RS-485 systems as well.

It can be difficult to quantify whether shielding is required in a particular system or not, until problems arise. We recommend erring on the safe side and using shielded cable. Shielded cable is only slightly more expensive than unshielded.

There are many cables available meeting the recommendations of RS-422 and RS-485, made specifically for that application. Another choice is the same cable commonly used in the twisted pair Ethernet cabling. This cable, commonly referred to as Category 5 cable, is defined by the EIA/TIA/ANSI 568 specification. The extremely high volume of Category 5 cable used makes it widely available and very inexpensive, often less than half the price of specialty RS-422/485 cabling. The cable has a maximum capacitance of 17 pF/ft (14.5 pF typical) and characteristic impedance of 100 ohms.

Category 5 cable is available as shielded twisted pair (STP) as well as unshielded twisted pair (UTP) and generally exceeds the recommendations for RS-422 making it an excellent choice for RS-422 and RS-485 systems.

For more information on serial communications, including RS485 systems issues, we recommend Serial Port Complete by Jan Axelson.

Basics of the RS-485 Standard

This information touches on some of the most commonly asked aspects of RS-485 communications. B&B Electronics has a free application note available on RS-422/485 that gives a more complete picture of RS-485 networks. Request B&B's RS-422/485 Application Note, available by mail or on our websites, www.bb-elec.com or www.bb-europe.com

What is an RS-485 network? RS-485 allows multiple devices (up to 32) to communicate at half-duplex on a single pair of wires, plus a ground wire (more on that later), at distances up to 1200 meters (4000 feet). Both the length of the network and the number of nodes can easily be extended using a variety of repeater products on the market.

How does the hardware work? Data is transmitted differentially on two wires twisted together, referred to as a "twisted pair." The properties of differential signals provide high noise immunity and long distance capabilities. A 485 network can be configured two ways, "two-wire" or "four-wire." In a "two-wire" network the transmitter and receiver of each device are connected to a twisted pair. "Four-wire" networks have one master port with the transmitter connected to each of the "slave" receivers on one twisted pair. The "slave" transmitters are all connected to the "master" receiver on a second twisted pair. In either configuration, devices are addressable, allowing each node to be communicated to independently. Only one device can drive the line at a time, so drivers must be put into a high-impedance mode (tri-state) when they are not in use. Some RS-485 hardware handles this automatically. In other cases, the 485 device software must use a control line to handle the driver. (If your 485 device is controlled through an RS-232 serial port, this is typically done with the RTS handshake line.) A consequence of tri-stating the drivers is a delay between the end of a transmission and when the driver is tri-stated. This turn-around delay is an important part of a two-wire network because during that time no other transmissions can occur (not the case in a four-wire configuration). An ideal delay is the length of one character at the current baud rate (i.e. 1 ms at 9600 baud). The device manufacturer should be able to supply information on the delay for their products.

Two-wire or four-wire? Two-wire 485 networks have the advantage of lower wiring costs and the ability for nodes to talk amongst themselves. On the downside, two-wire mode is limited to half-duplex and requires attention to turn-around delay. Four-wire networks allow full-duplex operation, but are limited to master-slave situations (i.e. a "master" node requests information from individual "slave" nodes). "Slave" nodes cannot communicate with each other. Remember when ordering your cable, "two-wire" is really two wires + ground, and "four-wire" is really four wires + ground.

How does the software work? 485 software handles addressing, turn-around delay, and possibly the driver tri-state features of 485. Determine before any purchase whether your software handles these features. Remember, too much or too little turn-around delay can cause troubleshooting fits, and delay should be a function of baud rate. If you're writing your own software or using software written for an RS-232 application, be certain that provisions are made for driver tri-state control. Luckily, there are usually hardware alternatives for controlling driver tri-stating. Contact B&B Technical Support for further details.

Connecting a multidrop 485 network. The EIA RS-485 Specification labels the data wires "A" and "B", but many manufacturers label their wires "+" and "-". In our experience, the "-" wire should be connected to the "A" line, and the "+" wire to the "B" line. Reversing the polarity will not damage a 485 device, but it will not communicate. This said, the rest is easy: always connect A to A and B to B.

Signal ground, don't forget it. While a differential signal does not require a signal ground to communicate, the ground wire serves an important purpose. Over a distance of hundreds or thousands of feet there can be very significant differences in the voltage level of "ground." RS-485 networks can typically maintain correct data with a difference of -7 to +12 Volts. If the grounds differ more than that amount, data will be lost and often the port itself will be damaged. The function of the signal ground wire is to tie the signal ground of each of the nodes to one common ground. However, if the differences in signal grounds is too great, further attention is necessary. Optical isolation is the cure for this problem. Contact B&B Technical Support for more details.

RS 422/485

Introduction
The purpose of this application note is to describe the main elements of an RS-422 and RS-485 system. This application note attempts to cover enough technical details so that the system designer will have considered all the important aspects in his data system design. Since both RS-422 and RS-485 are data transmission systems that use balanced differential signals, it is appropriate to discuss both systems in the same application note. Throughout this application note the generic terms of RS-422 and RS-485 will be used to represent the EIA/TIA-422 and EIA/TIA-485 Standards.
Data Transmission Signals

Unbalanced Line Drivers
Each signal that transmits in an RS-232 unbalanced data transmission system appears on the interface connector as a voltage with reference to a signal ground. For example, the transmitted data (TD) from a DTE device appears on pin 2 with respect to pin 7 (signal ground) on a DB-25 connector. This voltage will be negative if the line is idle and alternate between that negative level and a positive level when data is sent with a magnitude of ±5 to ±15 volts. The RS-232 receiver typically operates within the voltage range of +3 to +12 and -3 to -12 volts as shown in Figure 1.1.

Asustek Installs New Microprocessors, Graphics Chips, Larger Hard Drives, Adds HDMI Support to Eee Box

Despite of hype, the Asus Eee Box nettop from Asustek Computer has not turned out to be a massive success, unlike the Eee PC netbooks. In a bid to improve popularity of the Eee Box, the firm unveiled new versions of the product with discrete graphics chip as well as HDMI support. Moreover, there are Eee Box solutions incoming with more advanced central processing unit (CPU) inside.

This week Asus unveiled its Eee Box B204 and B206 (with integrated battery that performs U.P.S. function) that are still based on is based on Intel Atom processor N270 (1.60GHz), Intel core-logic and feature 1GB of DDR2 memory, but now come with ATI Radeon HD 3400-series graphics cards with 256MB of memory onboard, high-definition multimedia interface as well as 160GB hard disk drive. The systems come equipped with remote controller. The new Eee Box machines still lack optical drive, but they feature 4-in-1 card reader, Gigabit Ethernet, Wi-Fi 802.11n controller and, most importantly, Windows XP Home operating system.

The inclusion of HDMI connectors as well as remotes is likely to attract attention of multimedia enthusiasts who would use the Eee Box in their living rooms. In addition, with HDMI support, the systems gain compatibility with multimedia-oriented displays with HDMI connectors.

But that is not all. In the coming weeks there will be more new Eee Boxes from Asustek. Instead of the single-core Intel Atom N270/1.60GHz that is presently installed into the Asus Eee Box, the company has reportedly decided to utilize Intel Celeron 220 chip with higher performance and also install larger 120GB hard disk drive into the device. The price of such systems will be lower than that of the initial Eee Box version to boost demand and will be about $240, according to DigiTimes web-site.

Low performance, insufficient storage space, too simplistic integrated graphics core and the lack of HDMI are the key reasons behind lackluster welcome of the Eee Box by the market. Unlike Eee PC, which provides ultimate mobility amid low price, a combination never seen before; the Eee Box could boast with low performance and affordable cost only, something that is very common since low-end PCs have been available since personal computer started to gain popularity back in the eighties.

With ATI Radeon HD 3400-series GPU inside, more capacious hard drive, HDMI support and remote controller, the Asus Eee PC B204/B206 can be easily considered as low-cost small form-factor PCs for the living room. Obviously, one can hardly play video games on such a systems, but the nettops of such kind should be fine for multimedia playback or streaming. Meanwhile, the rumoured Celeron-based Eee Boxes may gain acceptance on the market of office PCs.

What's new in the VLSI Microprocessors

Intel has launched new Pentium-4 processor.
The Pentium-4 is fabricated in Intel's 0.18 micron CMOS process. Its die size is 217 mm2, power consumption is 50W. The Pentium 4 is available in 1.4GHz and 1.5Hz bins. At 1.5GHz the microprocessor delivers 535 SPECint2000 and 558 SPECfp2000 of performance. Currently it is the second-performing general-purpose microprocessor. The world champion is Compaq/Digital Alpha 21264B CPU delivering 544 SPECint2000 and 658 SPECfp2000 at 833 MHz. The previous Intel chip, Pentium-III "Coppermine", had 442 SPECint2000 and 335 SPECfp2000 results at 1GHz.
Pentium-4 is the first completely new x86-processor design from Intel since the Pentium PRO processor, with its P6 micro-architecture, was introduced in 1995. Pentium-4' micro-architecture is known as NetBurst. It has many interesting features.
- Compared to the Intel Pentium-III processor, Intel's NetBurst micro-architecture doubles the pipeline depth to 20 stages. In addition to the L1 8 KB data cache, the Pentium 4 processor includes an Execution Trace Cache that stores up to 12 K decoded micro-ops in the order of program execution. The on-die 256KB L2-cache is non-blocking, 8-way set associative. It employs 256-bit interface that delivers data transfer rate of 48 GB/s at 1.5 GHz. The Pentium 4 processor expands the floating-point registers to a full 128-bit and adds an additional register for data movement. Pentium-4' Net Burst micro-architecture introduces Internet Streaming SIMD Extensions 2 (SSE2). This extends the SIM D capabilities that MM X technology and SSE technology delivered by adding 144 new instructions. These instructions include 128-bit SIMD integer arithmetic and 128-bit SIM D double-precision floating-point operations. Pentium 4 processor's 400 MHz (100 MHz "quadpumped") system bus provides up to 3.2 GB/s of bandwidth. The bus is fed by dual PC800 Rambus channel. This compares to 1.06 GB/s delivered on the Pentium-III processor's 133-MHz system bus. Two Arithmetic Logic Units (ALUs) on the Pentium 4 processor are clocked at twice the core processor frequency. This allows basic integer instructions such as Add, Subtract, Logical AND, Logical OR, etc. to execute in a half clock cycle. The integer register file runs also runs at the double frequency. Interesting is that the this method was firstly introduced by Elbrus team in their E2K processor design. The E2K design was described in Microprocessor Report article by Keith Diefendorff in Feb 1999.
For more information on the new Intel Pentium-4 processor see official Intek press-release

AMD Strains Silicon in New Microprocessors. Advanced Micro Devices Adopts New Chip Making Tech

Advanced Micro Devices is reportedly adopting strained silicon for an array of its processors that will be available this Fall. The design tweak is likely to improve the company’s ability to ship high-speed microprocessors while maintaining sufficient yield as well as keeping heat dissipation of the products into generally-acceptable envelope.

Silicon-on-Insulator and strained silicon appear to be the technologies that AMD, Intel and IBM pin a lot of hopes on during the next three to five years. Both technologies are intended to keep increasing the speed of current flowing through a microprocessor and to address the connected issues, such as power leakage. SOI adds a thin oxide layer to a silicon wafer in order to insulate the circuit against power leakage. Strained silicon, in its incarnation that is used by Intel Corp. and IBM, deposits a layer of silicon germanium on top of a silicon wafer. This stretches the silicon atoms to let electrons flow faster through a circuit.

According to reports from Semiconductor Reporter and CNET News.com, Advanced Micro Devices is incorporating strained silicon into all the firm’s 90nm microprocessors that started shipping last week. Additionally, the Sunnyvale, California-based chip maker is expected to use strained silicon with its future 130nm microprocessors, which is a rather surprising move, as chip makers typically tend to migrate to thinner fabrication processes to allow higher-speed chips and decrease production costs, but not to advance older-generation manufacturing technologies.

Representatives for Advanced Micro Devices are reported to have said that strained silicon approach of the company is different from what IBM and Intel Corp. use. Silicon can be strained as a byproduct of other design changes, but the AMD representative said the company intentionally incorporated new layers in chips to achieve straining, although AMD does not give a lot of details about its new technology.

IBM and AMD are developing 65nm manufacturing process in collaboration. AMD’s Silicon-on-Insulator process was originally developed by IBM.

new inventions

At the International Solid State Circuits Conference (ISSAC) today, IBM, Sony Corporation, Sony Computer Entertainment Inc. (Sony and Sony Computer Entertainment collectively referred to as Sony Group) and for the first time disclosed in detail the breakthrough multi-core architectural design – featuring supercomputer-like floating point performance with observed clock speeds greater than 4 G Hz – of their jointly developed microprocessor code-named Cell.

A team of IBM, Sony Group and Toshiba engineers has collaborated on development of the Cell microprocessor at a joint design center established in Austin, Texas, since March 2001. The prototype chip is 221 mm2, integrates 234 million transistors, and is fabricated with 90 nanometer SOI technology.

Cell's breakthrough multi-core architecture and ultra high-speed communications capabilities deliver vastly improved, real-time response for entertainment and rich media applications, in many cases 10 times the performance of the latest PC processors.

Effectively a "supercomputer on a chip" incorporating advanced multi-processing technologies used in IBM's sophisticated servers, Sony Group's computer entertainment systems and Toshiba's advanced semiconductor technology, Cell will become the broadband processor used for industrial applications to the new digital home.

Another advantage of Cell is to support multiple operating systems, such as conventional operating systems (including Linux), real-time operating systems for computer entertainment and consumer electronics applications as well as guest operating systems for specific applications, simultaneously.

Initial production of Cell microprocessors is expected to begin at IBM's 300mm wafer fabrication facility in East Fish kill, N.Y., followed by Sony Group's Nagasaki Fab, this year. IBM, Sony Group and Toshiba expect to promote Cell-based products including a broad range of industry-wide applications, from digital televisions to home servers to supercomputers.